Not sure, but they do make the most ruckus. They sleep there when it’s open and where they charge their phones until they get booted out...
The most “interesting” of them all is the Hollywood public library close to us. This is probably the only library in the US where they need at least 2 LAPD cars parked when it’s open due to some ‘activities’.
I was at the relatively new San Diego Main Public Library, a big improvement over the old building, where I witnessed a homeless (I assume) person taking a sponge bath in the bathroom. But even he was white!